Examples of how to use node-cassandra-client

node-cassandra-client-examples.js

var async = require('async');

function doSimpleConnect(callback) {
  
  var Connection = require('cassandra-client').Connection;
  
  // these are the connection parameters you need to connecto to Cassandra.
  var connectionOptions = {
    host: '127.0.0.1',
    port: 19170,
    keyspace: 'EXAMPLE_KS',
    use_bigints: false
  };
  
  var con = new Connection(connectionOptions);
  
  con.connect(function(err) {
    // if err != null, something bad happened.  
    // else, assume all is good.  your connection is ready to use.
    if (!err) {
      con.close(callback);
    } else {
      callback(err);
    }
  });
}

var PooledConnection = require('cassandra-client').PooledConnection;

function doPoolConnect(callback) {
  var conOptions = { hosts: ['127.0.0.1:19170'],
                     keyspace: 'EXAMPLE_KS',
                     use_bigints: false };
  var con = new PooledConnection(conOptions);
  con.shutdown(function() {
    // no error object by design.
    callback();
  });
}

function doComplexInsert(callback) {
  var conOptions = { hosts: ['127.0.0.1:19170'],
                     keyspace: 'EXAMPLE_KS',
                     use_bigints: false };
  var con = new PooledConnection(conOptions);
  var cql = 'UPDATE very_complex_cf SET ?=?, ?=?, ?=? where KEY=?';
  var params = ['string_col', 'string_value',
                'uuid_col', '6f8483b0-65e0-11e0-0000-fe8ebeead9fe',
                'int_col', 42,
                'complex_insert_row'];
  con.execute(cql, params, function(err) {
    // demonstrates use of a callback.  A simplification would have been:
    // con.execute(cql, params, callback);
    if (err) {
      console.log(err);
    }
    con.shutdown(callback);
  });
}

function doComplexBatchInsert(callback) {
  var conOptions = { hosts: ['127.0.0.1:19170'],
                     keyspace: 'EXAMPLE_KS',
                     use_bigints: false };
   var con = new PooledConnection(conOptions);
   con.execute('BEGIN BATCH USING CONSISTENCY ONE \
     UPDATE very_complex_cf SET ?=?, ?=?, ?=? where KEY=?; \
     UPDATE very_complex_cf SET ?=?, ?=?, ?=? where KEY=?; \
     UPDATE very_complex_cf SET ?=?, ?=?, ?=? where KEY=?; \
     APPLY BATCH;', 
     [
       'string_col', 'value for string col in row_1',
       'uuid_col', '6f8483b0-65e0-11e0-0000-fe8ebeead9ff',
       'int_col', 25,
       'complex_batch_row_1',
             
       'string_col', 'value for string col in row_1',
       'uuid_col', '6f8483b0-65e0-11e0-0000-fe8ebeeada00',
       'int_col', 26,
       'complex_batch_row_4',
             
       'string_col', 'value for string col in row_1',
       'uuid_col', '6f8483b0-65e0-11e0-0000-fe8ebeeada02',
       'int_col', 27,
       'complex_batch_row_3'
     ], 
     function(err) {
       if (err) {
         console.log(err);
       }
       con.shutdown(callback);
     }
   ); 
}

function doSelectAll(callback) {
  var conOptions = { hosts: ['127.0.0.1:19170'],
                       keyspace: 'EXAMPLE_KS',
                       use_bigints: false };
  var con = new PooledConnection(conOptions);
  con.execute('SELECT * from very_complex_cf', [], function(err, rows) {
    if (!err) {
      console.log(rows.length); // should be 4 at this point.
      rows.forEach(function(row) {
        console.log(row.key);
        
        // access column names and values by index.
        for (var i = 0; i < row.colCount(); i++) {
          console.log(row.cols[i].name);
          console.log(row.cols[i].value);
        }
        
        // access column values by hash.
        console.log(row.colHash['string_col']); // it's a string
        console.log(row.colHash['uuid_col']); // it's an instance of require('cassandra-client').UUID
        console.log(row.colHash['int_col']); // it's a number.
      });
    }
    con.shutdown(callback);
  });
}

function doSelectiveSelect(callback) {
  var conOptions = { hosts: ['127.0.0.1:19170'],
                         keyspace: 'EXAMPLE_KS',
                         use_bigints: false };
  var con = new PooledConnection(conOptions);
  con.execute(
    'SELECT uuid_col FROM very_complex_cf WHERE KEY=?', 
    ['complex_batch_row_1'], 
    function(err, rows) {
      if (!err) {
        // rows.length should == 1.
        var row = rows[0];
        console.log(row.key);
        console.log(row.colCount()); // should be 1 also.
        // getting the values out is an exercise for the reader.
      }
      con.shutdown(callback);
  });
}

function doComplexColumnNames(callback) {
  var conOptions = { hosts: ['127.0.0.1:19170'],
                           keyspace: 'EXAMPLE_KS',
                           use_bigints: false };
  var con = new PooledConnection(conOptions);
  var updateArgs = [ '6f8483b0-65e0-11e0-0000-fe8ebeead9ff', new Buffer([1,2,3,4,5]), 'uuid_row_1' ];
  async.series([
          function insert(callback) {
            con.execute('UPDATE complex_cf set ?=? where KEY=?', updateArgs, callback);
          },
          function select(callback) {
            con.execute('SELECT * from complex_cf WHERE KEY=?', ['uuid_row_1'], function(err, rows) {
              if (!err) {
                // rows.length should == 1.
                
                // first access the col by index (when you know it).
                // col name should be an instance of UUID.
                console.log(rows[0].cols[0].name); 
                // col value should be <Buffer 01 02 03 04 05>
                console.log(rows[0].cols[0].value);
                
                // if you don't know the col index, you need to use the col hash.
                // of course, this assumes you know the column name.
                // in this case, it should point to the same buffer already referenced.
                console.log(rows[0].colHash['6f8483b0-65e0-11e0-0000-fe8ebeead9ff']);
              }
              callback(err);
            });
          }
  ], function(err) {
    if (err) {
      console.log(err);
    }
    con.shutdown(callback);
  });
}

// run them all.
async.series([
        doSimpleConnect,
        doPoolConnect,
        doComplexInsert,
        doComplexBatchInsert,
        doSelectAll,
        doSelectiveSelect,
        doComplexColumnNames
], function(err) {
  if (err) {
    console.log(err);
  } else {
    console.log('all good');
  }
  process.exit(0);
});